Mobile Access#

Pair your phone once and every session on the computer is on it. The agent stays on your machine, with your files and your permission boundary.

Pairing#

Settings → Mobile Access, or during onboarding:

1. Install Happy from the App Store or Google Play. Desktop shows a QR code for the listing.
2. Scan the device QR Desktop shows next and approve the computer on the phone. One scan.
3. Desktop installs the happy CLI so happy claude and happy codex sessions reach the phone too. Needs Node.js and npm.

An already-linked computer is reused without another scan.

Already using Happy? Your account and sessions keep working. Connect Desktop from Settings → Mobile Access; the terminal CLI and Desktop's runtime appear on the phone as two machines on the same account.

Encryption#

The phone holds the account's primary key. Content is encrypted on one device and decrypted on another. The relay stores and forwards opaque blobs; it sees that machines and sessions exist and when they were active, not what is in them. Full write-up: Security & Encryption.

From the phone#

• Send messages, with encrypted images.
• Answer permission requests and questions. A phone reply is a trusted answer.
• Stop the turn.
• Switch model and effort. Change the permission mode.
• Start a session in a directory. A directory that does not exist becomes a request to create it, never a silent mkdir.
• Read files and the session's Git changes through the same boundary the agent has.

Troubleshooting#

• Never delete or reset ~/.happy. It is shared with the terminal CLI and holds history, configuration, and account state.
• A saved link can be offline; Desktop says "connected" only on live status.
• If the CLI daemon stopped after a reboot or crash, run Mobile Access setup again. Ordinary Desktop startup does not restart it.
• A lost phone or a conflicting saved account is a recovery conversation. Keep both sides until you choose.